1. Field of the Invention
The present invention relates to a valve-operating device for an engine, and particularly to an improvement in a valve-operating device for an engine, comprising: a camshaft which is disposed on one side of a plane including axes of a first valve and a second valve corresponding to one and the other of an intake valve and an exhaust valve and which has an axis substantially perpendicular to the plane; and a first rocker arm and a second rocker arm which are swingably carried on a rocker shaft disposed substantially perpendicular to the plane and through which the camshaft and the first and second valves are connected to each other, whereby the first and second valves are opened and closed by the rotation of the camshaft.
2. Description of the Related Art
A conventional valve-operating device is already known, as disclosed in Japanese Patent Application Laid-open No. 8-74524.
In the device disclosed in the above publication, the first and second rocker arms are operated by a single cam formed on the camshaft. Therefore, although the structure is simplified, the opening and closing timings provided to the first and second valves are limited.
If first and second cams are simply formed to be arranged axially on the camshaft in order to provide inherent opening and closing timings to the first and second valves, respectively, so that the first and second rocker arms can be driven individually by the cams, each of the rocker arms is inevitably provided with a complicated structure in order to avoid the interferences between the first cam and the second rocker arm and between the second cam and the first rocker arm.